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# encoding: utf-8
#
# The <code>:callback</code> option is also available for the formatted text
# methods.
#
# This option accepts an object (or array of objects) on which two methods
# will be called if defined: <code>render_behind</code> and
# <code>render_in_front</code>. They are called before and after rendering the
# text fragment and are passed the fragment as an argument.
#
# This example defines two new callback classes and provide callback objects
# for the formatted_text
#
require File.expand_path(File.join(File.dirname(__FILE__),
%w[.. example_helper]))
filename = File.basename(__FILE__).gsub('.rb', '.pdf')
Prawn::Example.generate(filename) do
class HighlightCallback
def initialize(options)
@color = options[:color]
@document = options[:document]
end
def render_behind(fragment)
original_color = @document.fill_color
@document.fill_color = @color
@document.fill_rectangle(fragment.top_left, fragment.width,
fragment.height)
@document.fill_color = original_color
end
end
class ConnectedBorderCallback
def initialize(options)
@radius = options[:radius]
@document = options[:document]
end
def render_in_front(fragment)
@document.stroke_polygon(fragment.top_left, fragment.top_right,
fragment.bottom_right, fragment.bottom_left)
@document.fill_circle(fragment.top_left, @radius)
@document.fill_circle(fragment.top_right, @radius)
@document.fill_circle(fragment.bottom_right, @radius)
@document.fill_circle(fragment.bottom_left, @radius)
end
end
highlight = HighlightCallback.new(:color => 'ffff00', :document => self)
border = ConnectedBorderCallback.new(:radius => 2.5, :document => self)
formatted_text [ { :text => "hello", :callback => highlight },
{ :text => " " },
{ :text => "world", :callback => border },
{ :text => " " },
{ :text => "hello world", :callback => [highlight, border] }
], :size => 20
end
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